New innovations in computer technology have allowed portable computers, such as laptops, tablets, media players, and cellular phones, to perform more tasks using less power. While new metals and transistors with lower resistivity have helped reduce power requirements significantly, the power requirements for bright electronic screens drain quite a bit of portable computer battery life. As used herein, a “portable computer” is any computer that is coupled to a rechargeable battery power source, preferably a power source that is located within a body housing of the computer.
Many computer screens have easily accessible brightness controls in order to decrease the screen's luminescence along the sides of the portable computer device or on an attached keyboard through use of a function key. This is especially useful when a user brings a portable computer into a dimly lit room when a brightly lit backlit screen is not necessary. Such portable computer screens, however, require a mindful human user to manually dim and brighten the screen according to need.
EP1696414 to Lowles teaches a light sensor coupled to the display of a portable computer, where the display automatically dims or brightens depending upon ambient light conditions. Using a light sensor to automatically control the brightness of a screen, however, can oftentimes increase the power drain on the portable computer system since powering and processing light sensor circuitry adds its own power drain. These and all other extrinsic materials discussed herein are incorporated by reference in their entirety. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
Unless the context dictates the contrary, all ranges set forth herein should be interpreted as being inclusive of their endpoints, and open-ended ranges should be interpreted to include commercially practical values. Similarly, all lists of values should be considered as inclusive of intermediate values unless the context indicates the contrary.
U.S. Pat. No. 6,791,566 to Kuratomi teaches a display device that could be coupled to a portable computer, where the image display has a non-uniform luminance across the screen, such that the center of the screen is brighter than the edges of the screen. By providing such a gradiated luminance, Kuratomi's display device reduces power consumption while focusing a user's attention towards the center of the display screen. Kuratomi's device may be useful when viewing an electronic microscope or camera, where a user is primarily focused on the center of the screen, but is far less useful when a user wishes to focus on other parts of the screen that are not centered.
U.S. Pat. No. 7,643,095 to Yoshii increases the luminance of a screen when the screen displays movies and television shows that require such increased luminance, but decreases the luminance of the screen when the screen displays text documents that do not require increased luminance. Yoshii's system is useful for systems that switch from a television input to a computer input, but is far less useful when used with portable computer systems that show both video media and text media on the same screen.
Thus, there is still a need for improved screen-dimming technologies that decrease power requirements of a screen.